package com.zzyl;

public class Singleton {
    private volatile static Singleton INSTANCE = null;

    private Singleton() {
    }

    public static Singleton getInstance() {
        if(null == INSTANCE) {
            synchronized (Singleton.class) {
                if(null == INSTANCE) {
                    INSTANCE = new Singleton();
                }
            }
        }
        return INSTANCE;
    }
}